The present invention relates to a wheel for at least partially muscle-powered vehicles and in particular for bicycles.
Many different types of bicycle wheels have become known in the prior art. Hollow rims tend to be used with the spoke nipples disposed in the region of the hollow space between the rim base and the rim well. For reinforcing the rim base, rim eyelets may be employed which, as shown e.g. in FIG. 6 of EP 0 715 001 B1, connect the rim well and the rim base in the radial direction. The rim eyelets reinforce among other things the rim base.
US 2003/0090141 A1 discloses a wheel for bicycles where a cylindrical spacer sleeve is inserted between the rim base and the spoke nipple in the region of the rim hollow so as to ease the spoke at the transition between its threaded portion for screw-fastening to the spoke nipple and the non-threaded spoke portion. The bearing surface of the spoke nipple at the cylindrical spacer sleeve may be spherical so as to allow angular orientation of the spoke. To ensure the function the US 2003/0090141 A1 requires the cylindrical spacer sleeve to be of such a height as to result in a spoke bend in the region of the wheel radius. A height of 5 mm has been found to be advantageous for the cylindrical spacer sleeve. This wheel shows the drawback that the region of the rim hollow must be designed very high in the radial direction to accommodate the cylindrical spacer sleeve and the spoke nipple.
For reducing the total weight of a wheel having a metal rim, EP 0 715 001 B1 shows in FIG. 8 a rim which had been subjected to chemical post-processing for reducing rim material in such a way as to retain reinforced areas at the spoke holes only.
U.S. Pat. No. 6,402,256 B1 describes as an alternative, mechanical post-processing of the rim wall thickness such that in the spoke hole areas the rim wall thickness is greater than in other areas. This also allows a reduced weight of the rim.
While a rim according to U.S. Pat. No. 6,402,256 B1 and also the rim according to EP 0 715 001 B1 can be manufactured lightweight and functional, manufacturing involves complicated steps, thus making the rims expensive.